Imperfections in final piece


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Shane1985
Shane1985
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Hi Guys,

After much blood sweat, tears and not giving up, I finally managed to make a Carbon Part which I am half happy with.

The only problem is I am finding holes in the cure resin, pin holes and air bubbles as pictured below.

I used fast hardener with the usual Epoxy as its only a small piece and allowed for it to degas for 15 minutes after stirring it thoroughly. I ran the infusion through and made sure that the epoxy being pulled through the catch pot side came though for a good while so any aired epoxy was removed. 

Then clamped off the feed line the the the catch line.

Last night was very cold probably about 1 degree but I had the heater in the shed, however when I got checked this morning the heater failed and I had to bring the part to finish curing this morning in front of a heater.

Once I demoulded I found the holes and air bubbles.

Any Help on how I can prevent this please? Its the second time this has happened. 

http://www.talkcomposites.com/Uploads/Images/cc51a0b8-fb19-4bf0-9735-0931.JPGhttp://www.talkcomposites.com/Uploads/Images/7df93709-bd1c-42db-a41e-5698.JPGhttp://www.talkcomposites.com/Uploads/Images/3fd27edf-2b0d-4ac7-8c9b-97d2.JPG




 


Shane
-Carbon Amateur-
*Never give up!*
Warren (Staff)
Warren (Staff)
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HI Shane,

Its hard to tell from the pictures EXACTLY what could cause the issue.  However already being 99% there, hopefully fine refining of your technique should be all that is needed.  Obvious things to check in more detail is bag leaks - perhaps after the initial leak check, do an extended leak check to be extra sure.  Your resin sounds ok in terms of degassing, however if you are working somewhere cool, the resin will be a little thicker than normal and thus the bubbles won't self degas as normal. Same during the infusion, being slightly more viscous it will take longer to infuse and less trapped air will come out. Extra care needs to be taken to avoid bridging or lifting of the material - a lot of your bubbles seem to be in the curvy areas so that could be a part of it.  Finally once you've clamped the vacuum port, allow the resin feed to stay open a little longer than before to allow a little more resin in. 

Hopefully you should get to the bottom of it soon!

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant
Shane1985
Shane1985
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Brilliant thanks Warren,

I think you may be on to a winner with the Bridging issue. I think I need to add more pleats and more bagging to the process.

I will give it a go and report back..

But first, I need more carbon and epoxy lol!

cheers

Shane


Shane
-Carbon Amateur-
*Never give up!*
Matthieu Libeert
Matthieu Libeert
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seen your pictures on your instagram where you tagged me Smile 
my phone is broken so I'm "instagram-offline" :p 

Like warren said it might be bridging OR maybe moist in the carbonfiber?! 
can be many things in fact; leaks, to much peelply on that spot, to much infusionmesh, resin not stirred well enough, a spot close to the resin in-out, cold/heat, demould to early, did you use spraytack (did you use to much there?) is it a spraytack for composites or not?! 

Many possible things you will need to figure out and the easiest and fastest way will probably be trial and error and keep a good eye on it everythime Smile

good luck

Matthieu Libeert
Founder MAT2 Composites X Sports
website:
www.mat2composites.com




Chris Smith
Chris Smith
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I also had this problem. After talking to warren we found out the vacuum pump wasn't strong enough and/or the resin is going in too fast. Try clamping the resin side and slow the feed a little. These are the problems I found and after doing all the above I pulled a perfect part. Good luck. 
GO

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